In an effort to restore coral reefs in the Mediterranean Sea, researchers have created artificial rubber algae that looks similar to coralline algae. According to the New Scientist, researchers have decided to mimic the coralline algae, Ellisolandia elongate, in the hopes that the artificial algae will play a similar ecological function to corals: “forming reefs using calcium carbonate structures that create diverse and complex environments”.

Motivations for Rubber Algae Reefs

Federica Ragazzola is a scientist from the University of Portsmouth, UK, who is spearheading this artificial reef project. She works with researchers from the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) “to explore whether artificial coralline algae reefs can protect the organisms living on them against ocean acidification, as well as acting as scaffolds for natural coralline algae reefs to grow.”

Coralline algae have a high ecological importance in shallow, temperate regions. They’re considered ecosystem engineers because they create habitats for a wide range of small invertebrates and keep them safe from physical stresses such as wave action. Unfortunately, ocean acidification poses an ongoing threat to the health of coral reefs. Since coralline algae builds reefs made from a soluble form of calcium carbonate, the reefs and associated species are vulnerable degradation from lower pH levels.

Details of Rubber Algae Deployment

Ragazzola and her team used a rubber elastic material (silicon elastomer) to match the properties of coralline algae as closely as possible. They made 90 synthetic mini reefs, each with 20 fronds, and anchored with a clear resin. According to Ragazzola, they chose materials that would be non-toxic to the marine environment.

In May, the research team put their rubber mimics near existing coralline algae reefs in the north-western part of Italy, in the Gulf of La Spezia. Since they made their artificial algae only 10 centimeters in diameter, they could easily place them in the center of the natural reefs to encourage marine organisms, such as crustaceans, mussels and worms, to move into the rubber features.

Monitoring the Artificial Reefs

Since the implementation of the reefs, the research team has been monitoring them closely to find out whether the rubber algae can host marine organisms. In the first month, they’ve already found signs of biofilms (“thin layers of viscous fluid produced by and containing bacteria and microalgae”) that have formed on some of their rubber algae. The appearance of biofilm would suggest that microorganisms are beginning to colonize the artificial reefs. According to Ragazzola, “After a year, you should start to see some of the species – crustaceans and worms as well as microorganisms invisible to the naked eye – establishing on the mimics, as well as the start of the covering of coralline algae”.

The research team is curious to find out whether the artificial reef will act as a scaffold for coralline algae to build on. If successful, these microenvironments can act as a buffer for lower pH levels and resistance to future changes in climate and marine environments. Ocean acidification can cause coralline algae reefs to slowly dissolve, but structures like the artificial rubber fronds, could offer a place for the coralline algae to grow. This, in turn, would give the marine organisms a place to live.

In 11 months, the research team will bring in some of the artificial reefs and associated animal species into the lab to test their response to lower pH levels. According to Chiara Lombardi of the ENEA, “This will clarify how the coralline algae reef might act as a buffer to help maintain animal diversity and abundance… Our results will be important for the planning of future protection”.